The invention relates to fashion jewelry, especially to an imitation gem having light refracting and ligh reflecting faceted surfaces.
Such imitation gems, developed by imitation of chandelier glasses, were formerly made of glass and recently of transparent plastic materials. Chandelier glasses have iridescent coatings which are made, for example, by applying to the glass silver sulfuric resinate in solution with certain additives and then baking the glass. The iridescent coatings so produced are semitransparent mirrors which increase the effects of light reflection and refraction on the surfaces of the glasses at the interface of glass and air.
In order to obtain as many iridescent surfaces as possible, a chandelier consists of glass sections arranged at a multitude of angles relative to one another similar to the surface cut of a diamond. In the manufacture of imitation gems, it has been attempted to imitate these geometric shapes, that is, it has been tried to provide the gems with many surfaces arranged at angles relative to one another so as to provide for certain reflection characteristics. It has been found, however, that such reflection alone cannot generate the effects of iridescence of the original chandelier glasses.
In imitation gems which have one particular display side, the reflection capabilities have been improved by applying light reflecting metal coatings to the back surfaces which are also disposed at various angles.
It is the principal object of the present invention to provide an imitation gem which reflects the light to a large degree in highly concentrated rays but also in refracted form.
High reflection and refraction of light rays on an imitation gem are obtained by forming the gem of a transparent semi shell with a cover mounted thereon and with facets formed on the concave inner and convex outer surfaces of the shell and on the cover.
Such a gem body has faceted surface areas not only on the outside as it has been known but it also has inner surface areas with facets formed thereon. It may consist of two identical half shells, each of which is faceted on its outer and on its inner surfaces. This results in a large number of facets which all are exposed to air, causing reflection of the light at all interfaces of the transparent body and air that is at the outer as well as inner surfaces of the shell. The large number of facets provides for a large number of mirror surfaces which reflect the light at their interface with air and which refract the light rays which pass through the shell walls. As a result, the imitation gem according to the invention appears quite sparkling. This effect can be even further pronounced if the inner surfaces of the exposed side of the shell are provided with a light reflecting metal coating. If the metal coating is made to be so thin that it is semitransparent for light, light rays will pass through the metal coating into the interior of the imitation gem. If then the inner surface of the other semi shell is also provided with facets and with a reflective metal coating which is preferably also semitransparent, the imitation gem will reflect, refract and pass light rays entering from the front but also from the back side. Such imitation gems may be used in the manufacture of sparkling fashion jewelry, especially highly attractive sparkling earrings and other pendants can be created.
Preferably, the facets on the inner concave and the outer convex surfaces of the semi shell are similar but the semi shells are angularly displaced with respect to one another by half the width of the facets so as to provide an even larger number of prismatic light refracting surfaces which are disposed at an angle to one another.
However, the inner and outer facets may be displaced relative to one another by less than half their diameter, for example, by one fourth of their diameter.
If it is desired to obtain a certain orientation of the reflected light, the curvature of the shells may be selected to be aspherical or otherwise shaped as desired. For economical manufacture, however, it is preferable if both semi shells are identical in shape and consist of transparent plastic material.
In place of interconnecting two semispherical shells, it is possible to mount a backplate on a semi shell which backplate is also preferably provided with facets. Such an arrangement is especially advantageous if the imitation gem is intended for use in clothing jewelry but it may also be used for earrings or pendants if the gem is to be relatively flat. A gem formed in this manner also has the effects of iridescence described earlier mainly, however, generated by the facets of the curved semi shell on which the backplate is mounted.